<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <h1>我是标题</h1>
    <form action="/" method="get">
        用户名： <input type="text" name="username" /><br>
        年龄： <input type="text" name="age" /> <br>
        <input type="submit" value="提交" />
    </form>
</body>
</html>